Why is this the answer?

The answer is sponge because this clever riddle uses a fun trick to describe a simple cleaning tool you probably see in your kitchen every day. A sponge is a super helper that soaks up spills and cleans messes, and the two clues in the riddle perfectly describe how it works. Let us look at the first part: "I'm full of holes." If you pick up a sponge and look very closely, you can see that its whole body is filled with thousands of tiny little spaces. These tiny spaces are called pores. If a sponge did not have these holes, it would be just a solid block and it would not be a good cleaner at all! The holes are the most important part of the sponge because they are the secret to its success in the kitchen or bathroom. Without the holes, the sponge would not be able to do its important job of making things clean. Now for the second part: "yet I'm full of water." This is the cleverest part of the riddle. Usually, if something has holes, the water would just run right out, like trying to carry water in a net. But the special material a sponge is made of is designed to trap the water inside those tiny holes. The sponge uses its many holes like tiny little cups to hold a surprising amount of liquid. Think about what happens when you press a dry sponge into a bowl of water. It grows bigger right away as all its little pores fill up. It is holding all that water without letting it leak everywhere right away, which is what makes it so great at cleaning. You can carry the wet sponge over to the sink, and then you give it a big squeeze to let the water rush out. The holes fill up with water to clean, and then you empty them out to rinse, ready for the next job. That is why a sponge is the perfect answer, because it is the one thing that can be full of holes and full of water at the exact same time. It is a fantastic tool that uses its holed body to capture and move water around.